1. Field of the Invention
The invention relates to a touch apparatus. More particularly, the invention relates to a vehicular optical touch apparatus.
2. Description of Related Art
As information technology, wireless mobile communication, and information home appliances have been rapidly developed and applied in recent years, input devices of a number of information products have evolved from conventional keyboards and mouse to touch panels for the purposes of convenience, miniaturization, and being user-friendly. Besides, the touch panel may be applied together with a display to form a touch panel display. Generally, touch panels may be categorized into resistive touch panels, capacitive touch panels, optical touch panels, sound wave touch panels, electromagnetic touch panels, and so on.
In the known optical touch panel, an infrared light source emits infrared light to a surface of the touch panel, and the infrared light is reflected to an image detector within the touch panel when a user's finger is in contact with the surface of the touch panel. The touch location of the finger may be determined by the infrared light detected by the image detector. Nonetheless, if the infrared light in the ambient light passes through the touch panel and travels to the image detector within the panel, the infrared light may interfere with the image detector. Particularly, given that the ambient light is rather intense (e.g., the ambient light is the sunlight), the infrared light in the ambient light may even cause the image detector to encounter the issue of overexposure. Thereby, the touch location of the finger may be barely determined according to the image detected by the image detector.
U.S. Pat. No. 8,144,271 discloses a multi-touch sensing system that includes a light guide tube, a light source, a deformation layer, and an image detector.